To solve the system of linear equations given:
9x = 27 - 9y
20x = 71 - 9y
1. Begin by isolating y in one of the equations. Let's use the first equation:
9x = 27 - 9y
9y = 27 - 9x
y = (27 - 9x) / 9
y = 3 - x
2. Substitute the value of y in terms of x (y = 3 - x) into the second equation to solve for x:
20x = 71 - 9(3 - x)
20x = 71 - 27 + 9x
20x - 9x = 71 - 27
11x = 44
x = 44 / 11
x = 4
3. Now that we have found the value of x, substitute it back into the equation y = 3 - x to find y:
y = 3 - 4
y = -1
Therefore, the solution to the system of linear equations is x = 4, y = -1.